Surface-emitting laser including two-dimensional photonic crystal

Abstract

A surface-emitting laser includes an active layer and a two-dimensional photonic crystal and has a resonance mode in an in-plane direction of the two-dimensional photonic crystal. The two-dimensional photonic crystal is composed of a semiconductor and dielectric material that has a refractive index different from that of the semiconductor and acts as the photonic crystal holes being arranged into a two-dimensional periodical structure. When the lattice constant of the two-dimensional photonic crystal is a and the radius of the dielectric material acting as the photonic crystal holes is r, r≧0.22a. The dielectric material has a refractive index that causes the coupling coefficient of the two-dimensional photonic crystal to exhibit an increasing tendency as the distance between the active layer and the two-dimensional photonic crystal shortens.

1 . A surface-emitting laser comprising:
 an active layer; and   a two-dimensional photonic crystal including:
 a semiconductor, and 
 dielectric material that has a refractive index different from that of the semiconductor and acts as photonic crystal holes arranged in a two-dimensional periodical structure, 
   wherein the surface-emitting laser has a resonance mode in an in-plane direction of the two-dimensional photonic crystal;   r≧0.22a, where a is the lattice constant of the two-dimensional photonic crystal, and r is the radius of the dielectric material; and   the dielectric material has a refractive index that causes the coupling coefficient of the two-dimensional photonic crystal to exhibit an increasing tendency as the distance between the active layer and the two-dimensional photonic crystal shortens.   
     
     
         2 . The surface-emitting laser according to  claim 1 , wherein the refractive index of the dielectric material is between 2.0 and 2.3 inclusive. 
     
     
         3 . The surface-emitting laser according to  claim 2 , wherein the radius r of the dielectric material is 35 nm or more. 
     
     
         4 . The surface-emitting laser according to  claim 2 , wherein the distance between the active layer and the two-dimensional photonic crystal is 40 nm or less.